Display panel driving device and driving method for saving electrical energy thereof

ABSTRACT

A display panel driving device is provided. The display panel driving device includes a host and a driving chip. The driving chip includes a store unit, a driving module and a transmitting interface unit. The host controls the transmitting interface unit to switch sources of image data received by the driving module according to content of the image data, so as to determine whether the driving module receives the image data from the store unit or not.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefits of U.S. provisionalapplication Ser. No. 61/524,286, filed on Aug. 16, 2011. The entirety ofthe above-mentioned patent application is hereby incorporated byreference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display panel driving device and adriving method thereof, and more particularly relates to a display paneldriving device which can greatly save electrical energy and a drivingmethod thereof.

2. Description of Related Art

In recent years, with the enhanced environmental protection awareness,the requirements of energy saving are paid much attention. All sorts ofmechanical equipments, home appliances and computer products related tothe electrical energy are developed for realizing the maximalperformance by using the least electrical power.

Regarding a display, generally speaking, in order to achieve theelectricity saving of static frames, a panel driving chip is equippedwith a Random Access Memory (RAM). If image data content that drives thedisplay panel is static frames (for example, photos), a host of thedisplay stops updating the data in the RAM and the displayed image datamay be directly acquired from the RAM. Therefore, the host and the datatransfer interface of the driving chip do not necessarily provide thedisplay data, thereby reducing the power consumption.

The conventional driving manner of the display panel may achieve thepurpose of electricity saving, but when the image data content thatdrives the display panel is dynamic frames (for example, a movie), thehost of the display must continuously update the data in the RAM. Withthe increase of the resolution of the screen, the RAM in the drivingchip is required to have a large capacity. Hence, the power consumptionis increased, which results in that the conventional driving manner ofthe display panel cannot satisfy the low power consumption requirementin the industrial applications.

SUMMARY OF THE INVENTION

The present invention is directed a display panel driving device,thereby greatly reducing an electrical energy consumed for driving thedisplay.

The present invention provides a display driving device, which includesa host and a driving chip. The host is used to output a switchinginstruction and image data. The switching instruction is related tocontent of the image data. The driving chip drives a display panel todisplay frames according to the image data. The driving chip includes astore unit, a driving module and a transmitting interface unit. Thestore unit is used to store the image data. The driving module iscoupled to the store unit, for driving the display panel to display theframes according to the image data. The transmitting interface unit iscoupled to the host, the store unit and the driving module, and iscontrolled by the switching instruction to transmit the image data to atleast one of the store unit and the driving module, so as to determinewhether the driving module receives the image data from the store unitor not.

In an embodiment of the present invention, when the content of the imagedata is dynamic frames, the host disenables the store unit and controlsthe transmitting interface unit to transfer the image data to thedriving module. When the content of the image data is static frames, thehost disenables the transmitting interface unit and controls the drivingmodule to receive the image data from the store unit.

In an embodiment of the present invention, the image data includes aplurality of frames. A display period of each frame includes an imagedata transmitting period and an instructing period. When the content ofthe image data converts from the dynamic frames to the static frames,the host outputs an enable instruction in an instructing period of thelast dynamic frame, so as to enable the store unit to store data of thefirst static frame in an image data transmitting period of the firststatic frame, and output the switching instruction in an instructingperiod of the first static frame, so as to control the driving module toreceive data of a second static frame from the store unit in an imagedata transmitting period of the second static frame.

In an embodiment of the present invention, when the content of the imagedata converts from the static frames to the dynamic frames, the hostoutputs a disenable instruction and a switching instruction in thedisplay period of the static frames, so as to respectively disenable thestore unit and control the driving module to receive the image data fromthe transmitting interface unit in the image data transmitting period ofthe dynamic frames.

In an embodiment of the present invention, the display period of eachframe further includes a synchronizing period. The host synchronizes aframe separating signal output by the driving chip in the synchronizingperiod according to a vertical synchronization signal. The frameseparating signal instructs a start point of the display period of eachframe.

In an embodiment of the present invention, the host stops providing theimage data in the period that the driving module receives the image datafrom the store unit.

In an embodiment of the present invention, the driving module includes atiming controller and a driving unit. The timing controller is coupledto the transmitting interface unit and the store unit, for outputting adriving clock signal according to the image data. The driving unit iscoupled to the timing controller, for driving the display panel todisplay the frames according to the driving clock signal.

In view of the above description, the present invention determines thesources of the image data received by the driving module according tothe content of the image data, so as to effectively reduce the powerconsumption for driving the display panel.

In order to make the aforementioned features and advantages of thepresent invention comprehensible, embodiments accompanied with figuresare described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic view of a display panel driving device accordingto an embodiment of the present invention.

FIG. 2 is a schematic view of a display panel driving device accordingto another embodiment of the present invention.

FIG. 3 is a schematic view of driving a display panel when contentconverts from dynamic frames to static frames according to an embodimentof the present invention.

FIG. 4 is a schematic view of driving the display panel when the contentconverts from the static frames to the dynamic frames according to anembodiment of the present invention.

FIG. 5 is a flow chart of a display panel driving method according to anembodiment of the present invention.

FIG. 6 is a flow chart of driving the display panel when the contentconverts from the dynamic frames to the static frames.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

FIG. 1 is a schematic view of a display panel driving device accordingto an embodiment of the present invention. Referring to FIG. 1, thedisplay panel driving device 100 includes a host 102 and a driving chip104. The host 102 is used to provide image data D1, and the driving chip104 is used to drive a display panel 106 to display frames according tothe image data D1. As shown in FIG. 1, the driving chip 104 includes astore unit 108 and a driving module 110 coupled to the store unit 108.The store unit 108 is used to store the image data D1 provided by thehost 102, and the driving module 110 is used to drive the display panel106 to display the frames according to the image data.

The host 102 switches sources of the image data D1 received by thedriving module 110 according to content of the image data D1. In otherwords, the host 102 may determine whether the driving module 110retrieves the image data D1 from the store unit 108 to drive the displaypanel 106 to display the frames according to the content of the imagedata D1. For example, when the host 102 determines that the content ofthe image data D1 is the dynamic frames, the host 102 disenables thestore unit 108, so that the driving module 110 directly drives thedisplay panel 106 to display the frames according to the image data D1transferred from the host 102. When the host 102 determines that thecontent of the image data D1 is the static frames, the host 102 enablesthe store unit 108 and stores the image data D1 in the store unit 108,so that the driving module 110 may retrieve the image data D1 from thestore unit 108 to drive the display panel 106 to display the frames.When the image data D1 according to which the driving module 110 drivesthe display panel 106 comes from the store unit 108, the host 102 is notrequired to provide the image data D1 to the driving chip 104, so thehost 102 enters a low power mode to reduce the power consumption.

As described above, by switching the sources of the image data D1according to which the driving module 110 drives the display panel 106according to the content of the image data D1, the power consumption maybe reduced when the display panel 106 displays the static frames.Furthermore, when the display panel 106 displays the dynamic frames, bydriving the display panel 106 directly according to the image data D1transferred from the host 102, the dynamic frame data is prevented frombeing continuously written into the store unit 108, thereby greatlyreducing the power consumption.

FIG. 2 is a schematic view of a display panel driving device accordingto another embodiment of the present invention. Referring to FIG. 2, thedifference between the display panel driving device 200 of thisembodiment and the display panel driving device 100 lies in that thedriving chip 104 in the display panel driving device 200 may furtherinclude a transmitting interface unit 202 coupled to the host 102, thestore unit 108 and the driving module 110. In addition, the drivingmodule 110 may include a timing controller 204 and a driving unit 206.The timing controller 204 is coupled to the transmitting interface unit202 and the store unit 108, and the driving unit 206 is coupled to thetiming controller 204 and the display panel 106. The timing controller204 is used to output a driving clock signal SD1 according to the imagedata D1, and the driving unit 206 is used to drive the display panel 106to display the frames according to the driving clock signal SD1.

The transmitting interface unit 202 may be, for example, a MobileIndustry Processor Interface (MIPI) Display Serial Interface (DSI),which is controlled by a switching instruction output by the host 102 totransfer the image data D1 to at least one of the store unit 108 and thedriving module 110, so as to determine whether the driving module 110receives the image data D1 from the store unit 108 or not, therebyachieving the purpose of reducing power consumption. The switchinginstruction is related to the content of the image data D1. When thecontent of the image data D1 is the dynamic frames or the static frames,the sources of the image data D1 according to which the driving module110 drives the display panel 106 are illustrated in the embodiment ofFIG. 1, so the details will not be repeated herein. It should be notedthat when the content of the image data D1 is the static frames, thatis, in the period that the image data D1 according to which the drivingmodule 110 drives the display panel 106 comes from the store unit 108,the transmitting interface unit 202 is not required to transfer theimage data D1. Therefore, the host 102 may disenable the transmittinginterface unit 202 in this period, and controls the driving module 110to receive the image data D1 from the store unit 108, thereby furtherreducing the power consumption.

In details, when the content of the image data D1 converts from thedynamic frames to the static frames, the host 102 enables the store unit108, and controls the transmitting interface unit 202 to transmit theimage data D1 to the store unit 108 and the driving module 110 at thesame time. FIG. 3 is a schematic view of driving the display panel whenthe content converts from the dynamic frames to the static frames.Referring to FIG. 3, the image data D1 includes a plurality of frames. Adisplay period of each frame includes a synchronizing period T1, animage data transmitting period T2 and an instructing period T3. Thesynchronizing period T1 is used to execute a synchronization actionbetween the image data D1 and a frame separating signal TE output by thedriving chip 104. The image data transmitting period T2 is used totransmit a horizontal synchronization signal HSYNC and the image dataD1. The instructing period T3 is used to transmit the instructions sentby the host 102.

The host 102 synchronizes the frame separating signal TE output by thedriving chip 104 in the synchronizing period T1 according to a verticalsynchronization signal VSYNC. The frame separating signal TE instructs astart point of each frame display period. In other words, a time pointat which the frame separating signal TE converts to a high logic levelis the start point of a frame.

When the content of the image data D1 converts from the dynamic framesto the static frames, the host 102 outputs an enable instruction CEN1 inan instructing period T3 of the last dynamic frame (that is, an(N−1)^(th) frame as shown in FIG. 3), so as to enable the store unit108. In this manner, the store unit 108 may store data of the firststatic frame in an image data transmitting period T2 of the first staticframe (that is, an N^(th) frame as shown in FIG. 3). The host 102outputs a switching instruction SW1 in an instructing period T3 of thefirst static frame, so as to control the driving module 110 to receivethe data of the first static frame from the store unit 108 in an imagedata transmitting period T2 of a second static frame (that is, an(N+1)^(th) frame as shown in FIG. 3). In this manner, the quality of thedisplay frame is prevented from being affected when the content convertsfrom the dynamic frames to the static frames. In addition, the host 102is not required to provide the image data D1 to the driving chip 104 atthe start of the second static frame, and may enter a low power mode toreduce the power consumption. In addition, the transmitting interfaceunit 202 is not required to transmit the image data D1 and may bedisenabled to further reduce the power consumption.

Additionally, when the content of the image data D1 converts from thestatic frames to the dynamic frames, the actuation of the drivingdisplay panel 106 is shown in FIG. 4. When the content of the image dataD1 converts from the static frames to the dynamic frames, the host 102is waken from the low power mode at the last static frame (that is, an(N−1)^(th) frame as shown in FIG. 4), and sends a disenable instructionDS1 and a switching instruction SW1, so as to respectively disenable thestore unit 108 and control the driving module 110 to receive the imagedata D1 from the transmitting interface unit 202 in the image datatransmitting period T2 starting from the dynamic frames (an N^(th) frameand an (N+1)^(th) frame as shown in FIG. 4). In this manner, the imagedata D1 is prevented from being continuously written in the store unit108 in the period that the content of the image data D1 is the dynamicframes, thereby greatly reducing the power consumption. It should benoted that when the content of the image data D1 is the static frames,the host 102 is not required to provide the image data D1, so a timepoint at which the host 102 sends the disenable instruction DS1 and theswitching instruction SW1 is not limited within the instruction periodT3 of the (N−1)^(th) frame.

FIG. 5 is a flow chart of a display panel driving method according to anembodiment of the present invention. Referring to FIG. 5, in view of theabove, the display panel driving method may include the following steps.Firstly, image data is provided (step S502). Then, sources of the imagedata received by a driving module are switched according to content ofthe image data, so as to determine whether the driving module receivesthe image data from a store unit or not (step S504), in which thecontent of the image data may be dynamic frames or static frames. Atlast, a display panel is driven to display frames according to the imagedata (step S506).

In details, the step S504 may include firstly determining whether thecontent of the image data is the dynamic frames or the static frames(step S5041). If the content of the image data is the dynamic frames,the image data is transferred to the driving module (step S5042). If thecontent of the image data is the static frames, the image data istransferred to the store unit, so that the driving module receives theimage data from the store unit (step S5043). When the content of theimage data is the dynamic frames, the store unit may be disenabled toprevent continuously writing the image data into the store unit, therebyreducing the power consumption. In the period that the driving modulereceives the image data from the store unit, as the image data of thedriving display panel is provided by the store unit, the image data isnot required to be provided to the driving module, thereby reducing thepower consumption.

FIG. 6 is a flow chart of driving the display panel when the contentconverts from the dynamic frames to the static frames. Firstly, when thecontent of the image data converts from the dynamic frames to the staticframes, in a period of the last dynamic frame, the store unit is enabled(step S602). Subsequently, in a period of the first frame after thecontent converts to the static frames, the image data is transmitted tothe store unit and the driving module at the same time (step S604).Then, the display panel is driven according to the image data (that is,the static frames) stored in the store unit (step S606). In this manner,the quality of the display frame is prevented from being affected whenthe content converts from the dynamic frames to the static frames.

In view of the above, the present invention determines the sources ofthe image data received by the driving module according to the contentof the image data, so as to effectively reduce the power consumption fordriving the display panel. When the content of the image data is thedynamic frames, the image data is directly transferred to the drivingmodule. When the content of the image data is the static frames, thestore unit provides the image data to the driving module. Moreover, whenthe content converts from the dynamic frames to the static frames, theimage data is transferred to the driving module and the store unit atthe same time, so as to prevent from affecting the frame quality of thedisplay panel.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A display panel driving device, comprising: ahost, outputting a switching instruction and image data, wherein theswitching instruction is related to content of the image data; and adriving chip, for driving a display panel to display frames according tothe image data, the driving chip comprising: a store unit, for storingthe image data; a driving module, coupled to the store unit, for drivingthe display panel to display the frames according to the image data; anda transmitting interface unit, coupled to the host, the store unit andthe driving module, and controlled by the switching instruction totransmit the image data to at least one of the store unit and thedriving module, so as to determine whether the driving module receivesthe image data from the store unit, wherein the image data comprises aplurality of frames, a display period of each frame comprises an imagedata transmitting period, an instructing period, and a synchronizingperiod including a frame separating signal, when the content of theimage data converts from static frames to dynamic frames, the hostoutputs a disenable instruction and the switching instruction in theimage data transmitting period of the last static frames before thesynchronizing period of the first dynamic frame, so as to respectivelycompletely disenable the store unit throughout a period for displayingentire dynamic frames and control the driving module to receive theimage data from the transmitting interface unit in the image datatransmitting period of the dynamic frames.
 2. The display panel drivingdevice according to claim 1, wherein when the content of the image datais the dynamic frames, the host completely disenables the store unit andcontrols the transmitting interface unit to transfer the image data tothe driving module, and when the content of the image data is the staticframes, the host controls the transmitting interface unit to transferthe image data to the store unit, disenables the transmitting interfaceunit, and controls the driving module to receive the image data from thestore unit.
 3. The display panel driving device according to claim 1,wherein when the content of the image data converts from the dynamicframes to the static frames, the host outputs an enable instruction inan instructing period of the last dynamic frame, so as to enable thestore unit to store data of the first static frame in an image datatransmitting period of the first static frame, and output the switchinginstruction in an instructing period of the first static frame, so as tocontrol the driving module to receive data of a second static frame fromthe store unit in an image data transmitting period of the second staticframe.
 4. The display panel driving device according to claim 3, whereinthe host synchronizes the frame separating signal output by the drivingchip in the synchronizing period according to a vertical synchronizationsignal, and the frame separating signal instructs a start point of thedisplay period of each frame.
 5. The display panel driving deviceaccording to claim 1, wherein the host stops providing the image data inthe period that the driving module receives the image data from thestore unit.
 6. The display panel driving device according to claim 1,wherein the driving module comprises: a timing controller, coupled tothe transmitting interface unit and the store unit, for outputting adriving clock signal according to the image data; and a driving unit,coupled to the timing controller, for driving the display panel todisplay the frames according to the driving clock signal.